Head mountable device

ABSTRACT

A head mountable device for detecting a functional disorder of the brain in a patient, comprising an LED display; at least one electrode for measuring electrical potential; the device being configured to be mountable on the head of a patient such that when mounted on the head of a patient the LED display is positioned before the eyes of a patient and the at least one electrode is positioned adjacent to the occipital lobe of the patient.

The present invention relates to an apparatus and method for detecting afunctional disorder of the brain and, in particular, to detect afunctional disorder of the brain by monitoring the electrical responseof the brain to a visual stimulus.

BACKGROUND OF THE INVENTION

Mild Traumatic Brain Injury (mTBI) and other functional disorders of thebrain can be the result of physical impact, in particular impact to thehead. Observed symptoms of mild Traumatic Brain Injury include loss ofmemory, lack of orientation and delay brain processing speed. Suchsymptoms are typically recognised as concussion.

Mild Traumatic Brain Injury is often experienced in high impact sports,for example rugby, AFL and American football, as well as in otherphysical collisions, for example motor accidents. However, methods ofdiagnosis for mild Traumatic Brain Injury are typically subjective andoften unreliable. For example it is difficult to detect mild TraumaticBrain Injury using MRI scans or CT scans.

Mild Traumatic Brain Injury is a dangerous condition. Patients sufferingthe condition require a prolonged recovery period. It is dangerous foran individual suffering mild Traumatic Brain Injury to receive a furtherimpact before having recovered fully from the condition. This isparticularly dangerous in a sports situation in which a decision needsto be made quickly as to whether a player should resume participation inthe game following a collision. A reliable assessment of whether theplayer has sustained mild Traumatic Brain Injury is required in alimited time period.

One widely implemented test to assess mild Traumatic Brain Injury,particularly in sports, is the Sport Concussion Assessment Tool (fifthedition), SCAT5. SCAT5 is a standardised assessment for evaluatingwhether an athlete has sustained mild Traumatic Brain Injury. SCAT5 iswidely used at all levels of sports to detect concussion and is endorsedby several sports governing bodies including FIFA, World Rugby and theInternational Olympic Committee. SCAT5 includes a series of functional,physical and neurocognitive tests performed on a potentially injuredplayer. SCAT5 includes an assessment using several tests including theGlasgow Coma Scale (CGS) to assess consciousness, the Maddocks Score toassess the immediate memory of the player, as well as further physical,balance, coordination and cognitive tests to assess the player.

Although SCAT5 is widely recognised and implemented, many parts of theanalysis are subjective. Consequently different physicians can concludea different diagnosis on the same player. And players themselves arelearning to provide answers to either downplay or alternativelyexaggerate their symptoms. Metanalysis of sensitivity and specificity ofthe test. This presents a problem to accurate diagnosis of the conditionof the player. Overall, there is a possibility for errors andinaccuracies in diagnosis of mild Traumatic Brain Injury usingsubjective tests including SCAT5.

Embodiments of the present invention address some problems of the priorart by providing a new apparatus and technique for assessing functionalperformance of the brain.

SUMMARY OF THE INVENTION

In a first aspect, the invention provides a head mountable device fordetecting a functional disorder of the brain in a patient, comprising:

-   -   an LED display;    -   at least one electrode for measuring electrical potential;    -   the device being configured to be mountable on the head of a        patient such that when mounted on the head of a patient the LED        display is positioned before the eyes of a patient and the at        least one electrode is positioned adjacent to the occipital        lobes of the patient.

In embodiments the LED display is configured to display a visualstimulus.

In embodiments the visual stimulus is a light pulse.

In embodiments the visual stimulus is white light.

In embodiments the visual stimulus pulses at a frequency of between 5 Hzto 60 Hz.

In embodiments the visual stimulus pulses at a frequency of 15 Hz.

In embodiments at least one electrode is configured to detect electricalsignals from the occipital lobes of the patient in response to thevisual stimulus when the device is mounted on the head of a patient.

Embodiments further comprise a processor configured to receive electricpotential signal data from the at least one electrode.

Embodiments further comprise a memory, the memory being configured tostore predetermined electrical potential values, wherein the processoris configured to compare received electric potential signal data withpredetermined electric potential data to detect a functional disorder ofthe brain.

In embodiments the predetermined electric potential values are at leastone of:

-   -   amplitude of the electric signal;    -   frequency of the electric signal; or,    -   latency of the electric signal.

In embodiments the functional disorder of the brain is concussion. Infurther embodiments the functional disorder is neurological impairment(acute or chronic) or other neurological disorders, for example dementiaor MS. Further embodiments comprise a wireless transmitter, the wirelesstransmitter configured to transmit the electric potential signal data tothe processor over a radio communications network.

Further embodiments comprise a receiver, the receiver configured toreceive activation signals for the LED display, the LED display beingconfigured to display a visual stimulus on receipt of an activationsignal.

In embodiments the receiver is a radio receiver configured to receiveactivation signals from a computing device across a wirelesscommunications network. In embodiments the wireless communicationnetwork is WiFi, Bluetooth or another suitable wireless communicationnetwork.

In a second aspect the invention provides a method for detecting afunctional disorder of the brain in a patient comprising the steps of:

-   -   providing a visual stimulus to a patient;    -   measuring an electrical response of the brain to the visual        stimulus using a plurality of electrodes; and,    -   comparing the electrical response of the brain to predefined        electrical data to detect a functional disorder of the brain.

In embodiments the visual stimulus is provided by an LED display and theelectrical response of the brain is measured by at least one electrode;the device being configured to be mountable on the head of a patientsuch that when mounted on the head of a patient the LED display ispositioned before the eyes of a patient and the at least one electrodeis positioned adjacent to the occipital lobe of the patient.

In a third aspect the invention provides a system for detecting afunctional disorder of the brain in a patient comprising:

-   -   a head mountable device according to claim 1; and    -   a receiver for receiving electric potential signal data from the        at least one electrode.

In a fourth aspect the invention provides a head mountable device fordetecting a functional disorder of the brain comprising lighting meansfor providing a visual stimulus to a patient and at least one electrodeto measure an evoked potential by the brain of the patient to the visualstimulus.

In a fifth aspect the invention provides a method for detecting afunctional disorder of the brain comprising the steps of providing avisual stimulus to a patient and measuring an evoked potential to thevisual stimulus.

Embodiments of the invention use electroencephalogram (EEG). Byrecording the brain's electrical activity at the level of the scalp,neuronal activity can be objectively analysed. EEG testing is low-riskand relatively low cost, making it ideal for widespread use.

Event-related potentials (ERPs) are a subset of EEG which evaluate thebrain's response to stimuli rather than examining passive activity.

Embodiments use visual evoked potentials (VEPs), a type of ERP, recordedfollowing pattern oscillation or flicker visual stimulus, to assess theintegrity of the visual pathway from the cornea to the V1 visual cortex.

Embodiments compare the variance or a pattern of variance of the VEPsfrom baseline or normative models

Embodiments of the present invention provide a device to challenge thebrain that subtle as well as extreme reductions in mentation(neurological function), such as occur with concussion (mild traumaticbrain injury), dementia and stroke for example, can be detected reliablyand in a repeatable fashion. In embodiments, the means of the challengerelate to the nature of the stimuli put to the brain, the means ofreliably presenting them and the effectiveness (sensitivity andspecificity) of measuring the results.

These detectable changes might be acute, i.e. following recent trauma,or chronic, representing sub-clinical damage that is not able to bevisualised on conventional imaging techniques (such as CT or MRI) ormore advanced functional modalities including fMRI and DTI (diffusiontensor imaging) etc.

In addition, analogous to a hearing test where the response to variousfrequencies is detected and then can be longitudinally monitored,embodiments determine and record the response to various stimuli, bothin isolation and in combination, to determine whether these differ fromprevious recordings in the same individual and to population norms.Embodiments of the device and its driving software can adapt subsequenttesting for that patient to particularly explore those areas ofdifference looking for deterioration or recovery.

Applied stimuli may have a test routine to determine and modulate theeffect is equal in each case to that desired.

As the stimuli in many cases will be faint, as will be the responses,the connectivity of the sensors to the brain is important. Typicalpassive (non-powered) EEG electrodes require a gel or saline solution tobe applied intermittently.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a front view of an embodiment mounted on the head of apatient;

FIG. 2 shows a rear view of an embodiment mounted on the head of apatient;

FIG. 3 shows a side view of an embodiment mounted on the head of apatient;

FIG. 4 shows an exploded view of an embodiment;

FIG. 5 shows a rear view of an embodiment;

FIG. 6 shows an underside view of an embodiment;

FIG. 7 shows a system including a headpiece and a computer processingunit;

FIG. 8 is a block diagram showing components in an embodiment; and

FIG. 9 is a flow diagram showing steps performed by an embodiment.

FIG. 10 is a graph showing measured response to a visual stimulus.

FIG. 11 is a graph showing measured response to a visual stimulus.

FIG. 12 is a diagram of setup for LCD monitor stimulus.

FIG. 13 shows stimulus images used. Top row is flash stimulus; bottom ispattern stimulus. Stimuli alternated between images.

FIG. 14 shows timing pattern for 15 Hz frequency. Note the H and Lpattern, using either the ‘white’ or ‘black’ stimulus.

FIG. 15 shows a flow chart of data analysis.

FIG. 16 A shows an example of the visual stimulus.

FIG. 16 B shows electrode positions.

FIG. 17 shows Fourier transformations of the frequency spectrum.

FIG. 18 is a perspective view of a second embodiment of a head mountabledevice.

FIG. 19 is an exploded view of a visor in the second embodiment.

FIG. 20 is an exploded view of the sensor housing in the secondembodiment.

FIG. 21 is an exploded view of sensor plates in the second embodiment.

FIGS. 22 and 23 are flow charts showing the operation of an embodiment.

FIG. 24 is a perspective view of a third embodiment.

FIG. 25 shows a component of the third embodiment.

DETAILED DESCRIPTION OF THE DRAWINGS Example 1

Referring now to the drawings there is shown a head mountable device fordetecting a functional disorder of the brain in a patient. FIGS. 1 to 3illustrate an embodiment of the device worn on the head of a patient.The device is configured to provide a visual stimulus to a patient andto measure the evoked potential from the visual response using aplurality of electrodes positioned adjacent and superficial to the skulloverlying the occipital lobes of the patient. The occipital lobes arethe parts of the brain largely responsible for visual processing.

Device 100 includes an opaque visor 1100 positioned over the eyes of thepatient. The visor includes an arrangement of LEDs on the inside of thevisor to which the patient's eyes are exposed (shown in FIG. 5). TheLEDs are arranged to provide a visual stimulus to the patient when thedevice is activated. The device 100 includes a housing 1200 arranged tobe positioned at the back of the patient's head. Housing 1200 includesat least one electrode for measuring electrical potentials generated bythe brain of the patient. Electrodes are positioned within housing 1200.The device is configured such that housing 1200 is located superficialto the skull overlying the region of the occipital lobes 150 of thepatient's head. Device 100 includes headband 1300 and support portion1400 to maintain the position of device 100 on the patient's head.

Arms 1500 and 1505 extend from headband 1300 and are configured to bepositioned behind the ears of a patient. Each arm 1500 to 1505 includesa reference electrode.

Reference electrodes are activated to detect a reference electricalpotential for the patient during exposure to a visual stimulus.

During activation of the visual stimulus the electrodes measureelectrical potential. The device uses the measured electrical potentialto detect a functional disorder of the brain as discussed in more detailbelow.

Device 100 is described in more detail with reference to FIGS. 4-6. FIG.4 shows an exploded view of device 100. Visor 1100 is opaque andconstructed from a polymer material. Visor 1100 is attached to bridge1120 to position visor 1100 on a patient's nose. Top bar 1130 isattached to visor 1100 to connect visor 1100 to headband 1300.

A further embodiment of the head mountable device is shown in FIGS.18-21.

The embodiment of FIGS. 18-21 has a different construction to that ofthe device of FIGS. 1-3 but includes equivalent components. Visor 1810(shown in exploded view in FIG. 19) is arranged to be positioned overthe eyes of a patient when device 1800 is positioned on the patient'shead. Sensor housing 1840 is positioned at the rear of the patient'shead. Sensor housing 1840 includes EEG sensors 1852, 1854, 1856configured to be positioned over the occipital lobes when the device ismounted on a patient's head. The device 1800 is held in position on thepatient's head by headband 1820, 1825. Additional support is provided bytop headband 1830. Headbands 1820, 1825, 1830 include adjustors 1822,1824, 1834 respectively to allow the device to be tightly fitted to apatient's head.

Visor unit 1810 includes opaque visor 1812. Headband fitting 1418 ispositioned inside opaque visor 1812 and includes a top extending portion1813 extending from the visor to provide an anchor point for topheadband 1830. Reference electrode 1815 is positioned within portion1813. Reference electrode 1815 provides a reference signal for use inanalysis of patient data. Notice that in the embodiment of FIGS. 18-21reference electrode is positioned around the forehead of the patient.This is in contrast to the embodiment of FIGS. 1-6 in which referenceelectrodes are positioned behind the ears of a patient. Visor 1810includes LED source 1818 to provide the visual stimulus to a user. Askin interface gasket 1819 is positioned to contact the face of thepatient when the device is mounted on the head.

The sensor housing 1840 is shown in exploded view in FIGS. 20 and 21.Sensor housing includes sensors 5218, 5418, 1856 mounted on sensorplates 1858. Sensor plate 1858 is shown in exploded view in FIG. 21 withsensors 1852, 1854, 1856 positioned within the sensor plate. Bluetoothmodule and battery are also positioned within sensor housing 1840.

A further embodiment of the head mountable device is shown in FIGS. 24and 25. These Figures only show the rear portion of the device, withoutany visor or visual stimulus screen.

In the embodiment of FIGS. 24 and 25, three EEG sensors 2410, 2412, 2414are mounted on sensor plate 2460. Two reference sensors 2420, 2422 arelocated above the EEG sensors on the sensor plate 2460. Sensor plate iscontained within sensor housing 2400.

Sensor housing is configured to be positioned on the head of a patientat the rear of the patient's head in order that the EEG sensors arepositioned over the occipital lobes when the device is correctlypositioned on the head of the patient.

The device has arms 2450, 2455 to support the device on the head of thepatient. These arms may be connected to a visor.

LED Arrangement

An arrangement of LEDs 1110 is positioned on the inside of visor 1100.In the example of FIG. 5 LEDs 1100 are positioned in a rectangularconfiguration on each side of visor 1100. The arrangement includes rowsof four electrodes running horizontally across the inside surface ofvisor 1100 and three rows of electrodes running vertically down insidethe face of the visor. Electrodes are arranged in a uniformconfiguration having equal spacing between rows and columns. Electrodesare positioned symmetrically on both sides of the bridge and provide asymmetrical arrangement before each eye of the patient. In the exampleof FIG. 5, LEDs 1110 emit white light.

LEDs 1110 are powered by a battery positioned within housing 1200.Electrical power is provided to LEDs 1110 via electrical conductorspositioned within headband 1300, top bar 1130 and into visor 1110.

Housing 1200 also includes an LED driver. LED driver controls activationof each electrode within electrode arrangement 1110. LED driver controlseach LED independently. Consequently different illumination sequencescan be created including simultaneous illumination of LEDs, sequentialillumination of LEDs and selective activation of LEDs. LED driver isprogrammable to implement multiple different LED illumination sequences.The flashing frequency or variation of flashing frequency is controlledby LED driver.

LED driver can provide activation and deactivation of electrodes atspecific frequencies. Typical illumination frequencies for LEDs 1110 arebetween 5 Hz to 60 Hz. Preferred embodiments illuminate LEDs 1110 atoperational frequency of 15 Hz.

This frequency range is desirable as the strongest visual response fromthe brain lies from 10-15 Hz, and for higher frequency responses, 40-60Hz.

In some embodiments, intermittent lighting sequences are used includingperiodic bursts of lighting (stimulation periods) and breaks. Thestimulation periods may be regular or irregular. Typical breaks betweenstimulation periods may be 0.1 to 100 seconds. For example a first 30second stimulation burst may be followed by a 10 second break, followedby a further 30 second stimulation period, followed by a further 10second break, followed by a further stimulation period. The duration ofthe stimulation periods and breaks may be varied and the light sequencesmay be varied depending on the operating parameters for the system. Thedurations of the stimulation periods and breaks can be optimally set atintervals that may produce more pronounced results.

The stimulation may include sectoral variability of applied stimulus forthe visual field, for example different eyes may be isolated. This mayinclude left/right alternation, variance and sequencing with the abilityto isolate each eye and each visual field.

The time period pattern for stimulation may be varied in a sequence ofprogressively lengthening or randomly varying time periods to provideunique corresponding electric potential signals to distinguish latencyand avoid potential artefacts arising from conditioning.

In some embodiments the LED driver automatically sweeps through a seriesof frequencies and variations in periods of stimulation ornon-stimulation.

In some embodiments the LEDs are driven simultaneously to create thevisual stimulus. Alternative flashing arrangements may also be used inwhich LEDs are activated in an alternating flashing sequence or asweeping left-to-right (or right-to-left, top-to-bottom, bottom-to-top)flashing pattern. Additional lighting sequences are used in furtherembodiments.

Further embodiments include an LED shutter system that transmits orblocks ambient light to a controlled frequency by controlling‘opaqueness (from no transmissibility to close to full transmissibility)in the headset lenses instead of generating its own light. Typically theshutters are positioned in the glasses or visor. The shutter system mayhave a separate driver controlled by the processor or it may becontrolled by the LED driver.

Some embodiments use additional operational frequencies beyond the 5-60Hz range.

Preferred embodiments include white LEDs. White LED's may be constructedfrom a series of three smaller red, green and blue LED's which, whencombined, display a white colour. Alternatively, a blue LED incombination with yellow phosphor may also be used to generate a whiteLED.

Different wavelengths or variations in wavelengths may be used.

In addition to white LED's, addressable LED's may also be used to varythe colour output to acquire potentially different results.

Embodiments may utilise any range of preferred safe visible lightfrequencies ranging from near infra-red to blue light.

Brightness and intensity of the LED's may be adjusted manually from thesoftware as part of the initial setup. A hardware control is also to beused to control the LED's brightness and colour output.

In further embodiments, alternative light sources to LEDs are included.Further embodiments include combinations of LEDs with alternative lightsources.

Further embodiments of the invention include different arrangements oflight sources.

In further examples of the visor, the screen may be physicallypatterned, for example corrugated, for Visually Evoked Stimuli. Someembodiments of the visor include EMG on the screen to detect a physicalresponse to the light sequence, including blink response and aversion.

Further embodiments include polarised light elements.

Simultaneous different light patterns may be applied during the testsequence. Measurement of the EEG response allows detection ofsuppression of one or more of the applied stimuli.

Electrodes

Housing 1200 includes three active electrodes 1210. Electrodes areconfigured to measure electrical potentials of up to 100 μV.

A variety of electrodes may be employed in the system. The example ofFIG. 4 includes active electrodes which contain circuitry located a veryshort distance away from the electrode. This circuitry, which iscomprised of a pre-amplifier, allows the electrodes to have very highinput impedance, allowing use with dry skin.

Electrodes 1210 are connected to a processor positioned within housing1200. Processor controls activation and deactivation of electrodes 1210.

In further embodiments the number of electrodes and the specificposition of the electrodes may be varied.

Headband Configuration

Headband 1300 is configured to join housing 1200 to visor 1110. In theembodiment of FIGS. 3-6 headband 1300 is constructed in two pieces 1300a and 1300 b on either side of the device. Headband is constructed frompolymer material and is sufficiently flexible to allow comfortable andaccurate positioning of the device on the patient's head. Headband mayalso include length adjustors to facilitate accurate positioning of thedevice on heads having different circumferences. Headband 1300 includeselectrical wires to carry electrical input signals from housing 1200 tovisor 1110.

Headband 1300 includes plugs 1310 a, 1310 b for connection to top bar1130. Plugs 1310 a, 1310 b provides electrical connection betweenhousing 1200 and visor 1100. Plugs 1310 a, 1310 b also provide physicalconnection to top bar 1130.

At the rear of the device headband 1300 connects to housing 1200. Eachside of headband 1300 includes two connection points 1320 a, 1320 b tohousing 1200. Connection points provide electrical and physicalconnection between headband 1300 and housing 1200.

Support 1400 is positioned at the rear of the device. Support 1400 ismade from polymer and configured to hold the device in position on thehead of the patient. In particular, the shape of the support section1400 is rounded to hold the housing 1200 in close proximity to theoccipital lobes at the back of the head.

Device 100 includes two arms 1600 a, 1600 b extending from headband1300. Arms 1600 a, 1600 b are positioned behind the ears of the patientwhen being correctly worn. Arms 1600 a, 1600 b extend from headband1300. A reference electrode 1700 a, 1700 b is positioned at a distal endof each arm. Reference electrodes 1700 a 1700 b are active electrodes.Arms 1600 a, 1600 b include electrical wiring to carry activationsignals to reference electrodes 1700 a 1700 b and to transmit recordedsignals from the electrodes to housing 1200. Each of arms 1600 a, 1600 bincludes connector 1610 a, 1610 b configured to provide electricalconnection and physical connection to headband 1300.

In further embodiments the reference electrodes may be positioned atother locations around the patient, for example in housing 1200.

The positioning of the headset on a patient is illustrated in FIGS. 1-3when positioned on the head of a patient visor 1100 is arranged toposition LEDs directly in front of the eyes of the patient. The visor isarranged to provide full visual coverage to prevent visibility outsidethe LED array. Support section 1400 is rounded to engage the back of thepatient's head and to maintain the position of housing 1200 in closeproximity to the occipital lobes of the patient's brain. Arms 1500 arepositioned behind patient's ears and the reference electrodes arelocated in the region of the patient's ear lobes. Embodiments of theinvention facilitate adjustable sizing of the headband in order that thedevice can be worn by individuals having different head circumferences.

The positioning of the electrodes on the head can be controlled bycircuitry detecting electrode impedance to detect positioning and theadequacy of the contact to the head. The contact detectors detectcontact with the head and the position of the electrode on the head ofthe patient. For each patient a contact memory is created, this contactmemory may be a data file stored with the patient's record to record theposition of the electrodes. This allows electrode placement to bereplicated and allows the device to be positioned quickly and accuratelyon the patient's head.

Operation and Control of the Headset

The operational components of the headset and control device areillustrated in FIGS. 7 and 8. As discussed previously, headset 800includes LEDs 8010 activated by LED driver 8020 positioned in housing1200. The LEDs 8010 are connected to the LED driver via a series ofelectrical connections running through the headband between housing 1200and visor 1100. As discussed above, electrodes 8030 are located inhousing 1200 and configured to be in the proximity of the occipitallobes of the brain of the patient when the device is fitted to the headof a patient. Reference electrodes are also positioned on the headset,these may be positioned in various positions around the head dependingon the configuration of the headset, for example behind the patient ears(for examples FIGS. 1 to 3), above the sensor electrodes (see forexample FIGS. 24 to 26) or towards the front of the head (see forexample FIGS. 18 and 19). Further embodiments may include combinationsof positions for reference electrodes.

Electrical control of the headset is provided by processor 8040. Inpreferred embodiments of the invention processor 8040 is positioned inhousing 1200. However, it will be clear that processor 8040 could bepositioned at any location within the headset unit. Processor 8040provides activation information to LED driver 8020 which subsequentlycontrols activation of LEDs 8010. Processor 8040 also controlsactivation and deactivation of electrodes 8030. Electrodes 8030 areconnected to memory 8050. Memory 8050 receives the measured electricpotentials from each electrode, stores and transmits the values foranalysis.

Preferably, during a test, memory 8050 stores all information relatingto the activation sequence of the electrodes. Memory 8050 also storesthe measured potential values from each electrode in response to theactivation sequence. Further information relating to the test, forexample information regarding the location of the test, duration of thetest, and the date and time of the test may also be recorded in memory8050. The purpose of memory 8050 is to store data associated with thetest. Preferred embodiments of the invention include a memory modulewithin headset 100 but further embodiments may include a remotelypositioned memory connected the headset. The connection may be via awired connection or via a wireless connection. Headset 800 also includespower supply 8070 for providing power to the electrical components ofthe device.

Preferred embodiments to the invention provide wireless control of theheadset from a computing device across a wireless communicationsnetwork. Suitable wireless communications networks include WIFI,Bluetooth, mobile communication networks, or other suitable wirelesscommunication networks. In such embodiments a wireless module 8060 isincorporated into headset 800. Wireless module 8060 includes a radioreceiver to receive control information for headset 800 and a wirelesstransmitter to transmit performance data from headset 800 to acontrolling computer device.

FIG. 7 illustrates the connection between control device 850 and headset800. Control device 850 includes wireless module 8120 including a radioreceiver to receive performance data from headset 800 and a wirelesstransmitter to transmit control signals to headset 800. Control device850 includes user input device 8110. User input device is configured toreceive user input to control the computing device and consequentlyheadset 8110. User input device may be a keyboard, touch screen,microphone or other suitable device to receive a user instruction.Computing device 850 includes memory 8130. Memory 8130 includes standardoperating parameters for the headset and also stores performance resultsfor headset 800. Memory 8130 may include different operating sequencesfor headset 800 associated with different tests for a patient. Furtherembodiments of the invention store comparative results within a memoryof the computing device 8150. This may be within the same memory 8130 orwithin a separate memory unit. The comparative results are stored inorder that headset can compare measured electrical potential from theelectrodes with predefined results to diagnose a condition of thepatient. Computing device is controlled using processor 8140.

As discussed above, interaction between computing device 850 and headset800 is provided across a wireless communication network. In furtherembodiments communication may be provided between headset 800 andcomputing device 850 using a wired connection, for example a USB orother electrical or optical connector capable of exchanging data betweenthe devices.

In embodiments of the invention computing device 850 is a mobiletelephone. An application may be loaded onto the computing device toenable interaction with headset 800. Alternatively, a designatedcomputing device may be paired to headset 800. Any computing device withsuitable connectivity components and control components could be used tocontrol the headset and to interact with the headset.

Embodiments of the invention can be connected to the internet (“cloudbased storage systems” and “cloud based processing systems”). Suchsystems include communication modules in the headset and/or in thecomputing device to transmit and receive data across the internet orother data networks. Patient data and test data can be transmitted andreceived across these networks to enable remote storage and analysis ofpatient data. Data can also be retrieved for local analysis. In anexample, the capability of sharing processor and diagnostic data fromsingle and multiple systems with a software and dashboard interface canfacilitate review and analysis by a concussion specialist, team coach orsafety officer. The dashboard may provide real-time data as well ashistorical summaries for individual users, groups and populations.

Operation Procedure

FIG. 9 is a flow chart showing the steps taken during operation of anembodiment of the headset.

At 900 computing device 850 receives user input. Computing device 850 isconfigured to receive user input requesting the headset to undergo atest routine. In preferred embodiments the computing device includes atleast one preconfigured routine including specific parameters for thetest. Parameters may include duration of the test, sequence of LEDoperation, for example the frequency which LEDs are activated, number ofLEDs to be activated, the colour of the LEDs, the brightness of the LEDsor other operational parameters. Further parameters may includecombinations of periods of active and inactive lighting activity. Insome embodiments the user can manually override the preconfiguredparameters or can set parameters for a user defined test procedure. Theparameters and operation mode selected by the user are confirmed at 905.At 910 an operation initiation signal is transmitted to headset 800. Asdiscussed above, communications between the computing device 850 andheadset 800 may be implemented over a wireless communication network, awired network or any other suitable communication path.

Embodiments of the invention include a routine to ensure the device iscorrectly configured and positioned to receive clean EEG data. Thisinvolves having the subject have their eyes open for up to 30 secondsand then closed for up to 30 seconds whilst an initial recordingverifies that an EEG alpha rhythm is being received. Once that has beenascertained the rest of the testing sequence is initiated by thesoftware on the phone. If the EEG alpha rhythm is not received, stepsare suggested to improve electrode contact, reposition headset etc orcheck equipment functioning correctly.

At 915 the operation initiation signal is received at the headset fromthe communicating device. The processor initiates the electrodes on theheadset are activated at 920. A user may select to activate particularelectrodes within the headset for a particular test. For example aspecific number or group of electrodes.

In embodiments particular subsets of the electrodes can be activated fora particular test. In further embodiments on the invention an electrodeinitiation sequence is executed to confirm operation of activatedelectrodes.

After activation of electrodes processor 8040 initiates LED driver 8020.As discussed above, LED driver 8020 controls operation of LEDs 8010. LEDdriver 8020 initiates activation LED's in accordance with the user inputrequirements. As discussed above, LED driver controls activation of LEDsin accordance with the test requirements including activation ofparticular LEDs, length of stimulation periods, brightness of LEDs,colour of the LEDs, frequency at which LEDs are activated, variation inflashing frequency, intensity, wavelength, variation in wavelength, theorder in which LEDs are activated and the sequencing for activation. Asoothing component or sequence may be initiated pre-testing.

At 930 electrodes measure electrical potential during the test. Theelectrical potential measured by each electrode is stored at 935.

Measured electrical potential values may be stored locally in memory8050 or may be transmitted back to the computer device for storage atmemory 8130. In some embodiments measurements are stored locally andremotely. In some embodiments results are transmitted to cloud basedstorage and/or processors.

On completion of the test, LEDs and electrodes are deactivated.

Results Analysis

After completion of a test the electrical potential measurements fromthe electrodes are analysed. Preferred embodiments of the inventioncompare outputs of the electrical potential amplitude measured by theelectrodes. Preferably diagnostic algorithms are used to detect symptomsassociated with mild Traumatic Brain Injury. Parameters compared includethe time delay, amplitude, frequency associated with the measuredelectrical potentials and other parameters associated with theelectrical potential waveform. Systems detect the delay or discrepanciesin stimulated period lengths to detected period lengths or rest periods.

In preferred embodiments of the invention the electrical potentialmeasured by the reference electrodes is subtracted from the electricalpotential measured by the electrodes in the Occipital lobes to removeany background signals. The system looks for an alteration of visualevoked potential waveform amplitude or latency when compared to aprevious baseline or to a normative database.

In preferred embodiments of the invention the measured results arecompared with predefined results, for example baseline or normativemodels. These predefined results may have been taken previously, forexample for a sports team the results may have been taken in thepre-season to establish a baseline reading for the player. In furtherembodiments of the invention a predefined range is set outside thepredefined results beyond which functional disorder of the brain isdiagnosed.

In some embodiments results processing is performed entirely on-boardthe headset according to individual settings using memory 8050 andprocessor 8040. Further embodiments perform analysis using a combinationof on-board and internet (cloud based) analysis applied to the patientresults and across a population of patients, or categories of patients.

In preferred embodiments the diagnostic algorithms account for theindividual's historic measurements for detection in order to compare thecurrent performance of the patient's brain with its previous or normalperformance. Some diagnostic algorithms account for the historicmeasurements across user groups and populations. Analytics performedlocally on the headset, on the computing device or in the cloud and thediagnostic algorithms may be used to predict or infer the influence offatigue, time of day, exercise regimes, diseases, medications, a historyof concussion, a history of trauma or of other neurological disorders.

Embodiments of the invention compare the results and trigger an alert ifthe waveform of the potential measured by the electrodes is outside thepredefined range. The alert may be an audio alarm from the computerdevice or a visual alert from the computer device. Further embodimentsof the invention include alternative alert mechanisms, for examplevibrator devices, or networked messaging systems for example email.

In some embodiments, to better quantify the strength of the SSVEPresponse, an algorithm is used which utilises the mean amplitude,standard deviation and peak amplitude of the frequency response. Bytaking into account standard deviation, larger inconsistencies infrequency response are accounted for when rating the response. Thisrating is unitless.

The steps to this algorithm are as follows:

Step 1: Apply 3rd order Butterworth bandpass filter, with cornerfrequencies 5-35 Hz to data stream(s). This will normally be data fromelectrode positions O1, O2 and Oz.Step 2: Perform Fast Fourier Transform (FFT) with Hanning windowing ondata from step 1.Step 3: Combine data from step 2 into one dataset.Step 4: Calculate from data from step 3, the following:

-   -   (a) Average amplitude (μ) between 5 Hz to 35 Hz. In other words,        sum all values from the corresponding FFT bins between 5 Hz and        35 Hz, then divide by the number of bins.    -   (b) Standard deviation (σ) between 5 Hz to 35 Hz.    -   (c) Peak amplitude between (v) 14.5 Hz and 15.5 Hz. In other        words, the highest amplitude recorded between 14.5 Hz and 15.5        Hz.        Step 5: The rating is expressed as: Rating=(v−μ)/σ

FIGS. 10 and 11 show example graphical representations of a Fouriertransformation of signals measured by electrodes 1210. The graphs showthe frequency response of the electrodes. Typically, in healthyindividuals, a high and distinct fundamental frequency will be observedwith the frequency matching the frequency of the visual stimulus. FIG.10 shows a response measured by electrodes in a healthy individual. Ahigh and distinct response is measured at around 15 Hz. FIG. 11 shows aresponse measured by electrodes in an individual suffering a functionaldisorder of the brain. The graph of FIG. 11 shows a lower response whichis less distinct.

The frequency response for injured players typically yields a lessdefinitive fundamental frequency, or in more severe cases even lack thefundamental frequency.

A further detailed description of the set up and use procedure is nowdescribed with reference to FIGS. 22 and 23. The procedure of FIG. 22 isdescribed in relation to a clinician having a number of patientsexecuting the test on behalf of a patient. In the example of FIG. 22 theheadset is controlled via an application running on a computer or smartphone connected to headset across a communications network.

On establishing an active communications signal between the computer andthe headset and activating the necessary software on the computer theclinician opens the login page at 2202. If the clinician is not yetregistered he may register at this stage. The clinician's lists ofpatients is presented at 2210. In the case that the patient is not yetregistered under the clinician at 2212, patient information is includedinto the system at 2214. Any further authentication requirements, forexample photo ID or other further authentication requirements may be metat this stage. Patient list 2210, 2220 may be stored locally and mayalso be synchronised with cloud storage database. Further identificationchecks may be performed at 2216.

In order to prepare the system and the patient for testing the patientis seated at 2224. If the headset is plugged into a charging module thismust be removed at 2226. The headset may be prepared for use by cleaningand by the application of saline solution to the electrodes to ensurethe electrodes are wet to the touch at 2228. This decreases impedance ofthe EEG signals. At 2230 the headset is positioned on the head of thepatient. Headsets may be positioned differently depending on theparticular configuration of that headset but, typically, the headband ispositioned above the ears and adjusted to snuggly fit the patient. Theheadset is positioned symmetrically on the head.

Test procedures may be run at 2232 including impedance check, batterycheck may be tested for required power output and temperature of thedevice may also be checked to ensure it conforms to the necessarytemperature limits and connection test over Bluetooth or other wirelesscommunication network. If not conforming, an error message may bedisplayed.

At 2234 the preliminary EEG test based on alpha wave is conducted. Asdescribed above, this involves having the patient have their eyes openfor up to 30 second and providing no light stimulus. AT 2236 preliminaryEEG test is run with eyes closed for up to 30 seconds with no lightstimulus. An initial recording verifies that an EEG alpha rhythm isbeing received. If no EEG signal is detected at 2240 preliminary EEGtest is run again at 2238 until an EEG signal is detected at 2236. Aftera successful test at 2240 the patient proceeds to the first test.Patients are instructed to keep their eyes open for the duration of thefull test. The test is run at 2350 (FIG. 23). If errors are detected at2252 the test may be re-run. Further tests may be required at this stagefor verification of results. If no further tests are required theclinician can conduct the first assessment at 2358 and upon a successfultest, the results are saved and return to patient profile 2362 orprogress with further tests on other patients.

Embodiments of the invention provide a system and method for detecting afunctional disorder of the brain by measuring evoked potential from avisual response. Embodiments of the present invention provide anadvantage that the performance of the nerves within the brain can beassessed quickly, consistently and in a non-subjective manner. This isparticularly significant in a sporting environment in which a diagnosisis required to be made quickly. The electronic nature of the device alsoenables predefined results and previous player results to be stored andcompared at the time of the test in order to aid with the diagnosis.

As discussed above embodiments of the system are connected tocommunications networks to enable local or remote analysis and diagnosisof results. All results (including existing standard observations andtests) may be incorporated by the on-board, on-phone, or online systems(or any combination of these) by algorithms, including machine learningmethods, for concussion diagnosis or longer-term concussion researchthrough internet (“cloud”) analytics and detection of emergentrelationships that are not currently established.

Embodiments of the invention remove the need for subjective assessments.Instead, the tests conduct scientific measurements to assess theperformance of the nerves within the brain.

In the embodiments described above the headset is illustrated as asingle unit. In further embodiments of the invention the visor providingthe visual stimulus could be provided in a separate unit from theelectrode array. In further embodiments the housing need not include allelectrical components of the device but the LED driver, memory,processor, wireless modules and power supplies may be positioned withinother components of the system.

In the embodiments described above with reference to the figures thevisor is in the shape of a pair of sports glasses. Further embodimentsinclude alternative shaped visors. Other head wear suitable forpresenting a visual stimulation to the eyes of a user, for example, ahelmet or screen is included in the embodiments. Further embodimentsinclude various headsets, goggles and virtual reality visors.

In a further embodiment of the invention the system can be implementedand controlled via a smartphone, for example under the control of anapplication on the smartphone. The headset can be substituted by asmartphone providing a visual stimulus and electrode positioned over thevisual cortex in communication with the smartphone either by beingplugged directly into the phone in a wired connection (even through themicrophone/line in port) or mediated by a wireless or Bluetooth coupledcomponent. The smartphone may be used within a virtual reality typeholder. In such embodiments the application controls the visual outputand receives and analyses the electric potentials received from theoccipital sensors.

The smartphone can communicate guidelines and instructions to thepatient and test information as well as generate visual stimulationpatterns.

In further embodiment of the invention, the test routine may also auditthe user's vestibular sense and sensitivity through an onboard test thatutilizes, for example, a smartphone compass, accelerometer and gyroscopesensors. The screen utilize augmented or virtual reality conditions toinvoke challenges and controls for vestibular testing.

Embodiments of the invention may be used to “profile” a potentialpatient, for instance in pre-season testing of sports players who arelikely to suffer mild traumatic brain injury, in order to determine themodalities to which those patients are most sensitive in testing. Thiswill create a “thumbprint” or “passport” for that individual allowingthe most refined and sensitive testing following an injury and duringrecovery.

It may also be compared to normative data and responses to elucidate anindividual's susceptibility to change following trauma, or their“concussion threshold”.

After a collision or other event which could potentially result in ahead injury, the EEG test is run on the individual. The same test is runafter the collision as the profile test and the results are compared tomake an assessment of whether the individual has a disorder of thebrain.

Example 2

The aim of this study was to evaluate the utility of a portableelectrophysiology platform to record measurable SSVEPs from healthyindividuals.

Participants

All participants were screened for a history of epilepsy, seizures andexisting or previous brain injuries and conditions. Any positivefindings excluded the participant from the study.

Equipment

Two main components of the system were identified: the visual stimulusgeneration component, and the EEG recorder. A computer was used tocapture the data from the EEG recorder, and perform signal analysis onthe data. The visual stimulus was delivered in two separate setups: aportable smartphone setup, and another utilising a traditional LCDcomputer monitor. For the portable setup, a Sony Xperia Z1 Compactsmartphone (Sony Corporation, Minato, Tokyo, Japan) housed in a GoogleCardboard (Google Inc., Googleplex, Mountain View, Calif., U.S.A.) wasused. A Dell U2415 LCD monitor (Dell Technologies, One Dell Way, RoundRock, Tex., U.S.A.) was used as the traditional LCD monitor.

The EEG recorder was an Emotiv EPOC+ 14-channel portable wirelessheadset (Emotiv Inc., San Francisco, Calif., U.S.A.). This headset has14 saline-moistened electrodes and 2 more for acommon-mode-sense/driven-right-leg feedback system. Only the O1 and O2electrodes along with ground electrodes were used for recording theoutput from the occipital region relating to visual signals. The Emotivheadset includes software that runs under a Windows operating systemwhich captures data from the headset and records it into a European DataFormat (EDF) standard file format. The headset sampling rate was set to128 Hz. Processing of data was performed on MATLAB (MathWorks, Inc.,Natick, Mass., U.S.A.) with the use of the Signal Processing Toolbox.

The stimuli were generated on MATLAB in the form of a MP4 movie sequencefile. Two sets of stimuli were created: one incorporating a simpleflicker stimulus, the other with a checkered pattern stimulus. Bothstimuli incorporated a fixation target in the form of a centrally placednumber. As video compression can introduce compression artifacts, themovie file was inspected in Adobe Premiere CC frame-by-frame for anyframe artifacts (i.e. a black frame becoming grey). It was found to befree of such compression artifacts.

Environment

The experiments were performed in a quiet room. The response qualitywhen using the LCD display was significantly affected by environmentallight, and therefore all lights to the room were turned off duringtesting. Environmental conditions related to external noise, andintensity and directionality of ambient light sources were keptconsistent throughout all testing.

Experimental Setup

The experiment was divided into 2 separate stages. The first stageevaluated each parameter associated with SSVEPs and determined optimalparameters. The second stage validated the optimal parameters on alarger population. The EPOC+ headset was paired via Bluetooth to thecomputer and fitted to each participant. The appropriate impedance wasverified by the included software. Between each test there was oneminute of rest. All tests were repeated once.

For tests requiring the portable SSVEP, the smartphone was powered onand the stimulus was displayed. The smartphone was then housed in theGoogle Cardboard and provided to the user. The participant held thesystem in their hands, then held the unit to their face to observe thestimulus upon test commencement. The participant was sitting throughoutthe test.

For tests requiring the LCD computer monitor, the stimulus was displayedon the monitor. Users were required to sit 30 cm from the monitor asseen in FIG. 12.

Experiment I

The aim of Experiment I was to evaluate the optimal parameters for aportable SSVEP system, as well as comparing the portable system (thesmartphone/Cardboard combination) against LCD monitors conventionallyused for SSVEP applications. 4 parameters were evaluated: the deliveryplatform, type of stimulus image, stimulus frequency and epoch length.

Delivery Platform

A 30-second viewing of the stimulus was performed by the 4 subjectstwice for each platform. A 15 Hz flash stimulus with a fixation targetwas used.

Participants were initially evaluated on the computer LCD displaypositioned 30 cm from each participant. Once the stimulus commenced, allparticipants were instructed to concentrate on the fixation target. Therecording was started remotely on the computer connected via Bluetoothto the EPOC+.

Participants were next evaluated utilising the portable system. Afterconfirming they could see the stimulus, the recording was remotelystarted from the connected computer.

Stimulus Image

4 subjects were evaluated with a 30-second 15 Hz visual stimulus of botha pattern reversal and a flash pattern on an LCD monitor. Each stimulusimage was evaluated twice (FIG. 13). The order of the stimulus imageswas randomised for all participants. All participants were instructed toconcentrate on the fixation, then the recording was started remotely.

Stimulus Frequency

Both patterns with a fixation target were displayed at 12, 15, 20 and 30Hz, each for 30 seconds. The portable stimulus platform was used and all4 participants were evaluated twice for each frequency. The frequenciesand their associated frame output are seen in Table 3 and FIG. 14.

TABLE 3 Frequencies and Rendering Pattern for 60 Hz Table 3: Frequenciesand Rendering Pattern for 60 Hz Displays Frequency Period Pattern 6166.67 HHHHHLLLLL 6.66 150 HHHHHLLLL 7.5 133.33 HHHHLLLL 8.57 116.67HHHHLLL 10 100 HHHLLL 12 83.33 HHHLL 15 66.67 HHLL 20 50.00 HHL 30 33.33HL

Epoch Length

To evaluate all epoch lengths at once, all 4 participants were evaluatedfor 45 seconds with the portable stimulus platform, viewing a stimulusat 15 Hz of the flash-reversal pattern along with a fixation target.These epochs were cropped into 5, 10, 15 and 30-second segments foranalysis.

Experiment II

After evaluating the results from Experiment I, it was determined thatthe portable stimulus platform performed similarly to an LCD monitor,and that a 15 Hz flash stimulus with a fixation point and a length of 30seconds was optimal. All subjects were evaluated twice with theseparameters. A flow chart is seen in FIG. 15.

Data Analysis

All data from the Emotiv EPOC+ was captured with the Emotiv XavierTestbench software into a European Data Format (EDF) file.

Each EDF file was imported into MATLAB for preparation and analysis. TheO1 and O2 channels were selected for analysis. No downsampling ofsignals was required as the EPOC+ headset has already downsampled thedata from 2048 Hz to 128 Hz.

Signal Filtering

Both the O1 and O2 channels were filtered with a 3rd-order Butterworthbandpass filter with 5-40 Hz window. An infinite-impulse response-type(IIR) filter was chosen for its small delay and efficiency. Whenchoosing coefficients for the IIR filter, instability testing wasperformed using the MATLAB Signal Processing Toolbox (specifically theis stable function) to prevent uncontrolled filter outputs fromoccurring. For the filter design, a Butterworth IIR filter was chosendue to its lack of ripple in the passband.

The lower cut-off frequency was chosen due to high levels of noisepresent in the lower frequency caused by skin impedance. The highercut-off frequency was chosen to eliminate mains noise (occurring at 50Hz) and preventing aliasing. The Nyquist frequency was 64 Hz (as thesampling rate was 128 Hz), resulting in all frequencies beyond 64 Hzbeing aliased. In addition, as there was 50 Hz interference caused bysurrounding electrical appliances. A cut-off of 40 Hz filters thealiasing without resorting to a steeper and less stable filter.

The initial 5 seconds was cropped as user testing found that there wassignificant eye blinking whilst habituating to the stimulus as testingbegan, which then ceased.

Signal Transformation

A Fast Fourier Transform (FFT) was performed on the filtered O1 and O2channels. Only frequencies between 0-40 Hz were plotted, as frequenciesbeyond the bounds were filtered. The O1 and O2 channels were combinedtogether into one output.

Quantification of Response

A simple algorithm was proposed to quantify the frequency response. Theaverage background spectral activity (or noise) from 0-40 Hz wasacquired, and then a ratio between the peak 15 Hz magnitude and thebackground noise was recorded.

The equation can be expressed as:

Ratio_response=(Amplitude_15 Hz)/(Amplitude_average).

Statistical Analysis

All statistical analysis was performed on GraphPad Prism 7.02 (Graph PadSoftware, Inc., 5755 Oberlin Drive, #110, San Diego, Calif. 92121,U.S.A.). D'Agostino & Pearson normality tests were performed on the datato determine the distribution pattern.

Results

Experiment I

4 healthy adults (3 males, 1 female, Mage=21.5, SDage=1.708)participated in Experiment I. All 4 subjects had 20/20 vision, andsuccessfully completed all sections of Experiment I.

Delivery Platform

The mean Ratio Response of the LCD monitor was 6.415±0.627. Use of theportable platform yielded similar response ratios to the LCD monitor,with a mean Ratio Response of 6.199±0.501.

TABLE 4 Response for Different Delivery Plafforms Traditional SubjectLCD Portable 1 7.327 6.912 2 5.911 5.752 3 6.274 5.995 4 6.147 6.138Mean 6.415 6.199 SD 0.6265 0.5012

Stimulus Image

Both the pattern reversal and flash reversal images had similarresponses, with a mean Ratio Response of 6.142±0.353 and 6.199±0.443respectively.

TABLE 5 Response Ratios for Different Stimulus Images Subject Flash Rev.Pattern Rev. 1 6.721 6.634 2 5.625 5.807 3 6.015 6.120 4 5.865 6.006Mean 6.057 6.142 SD 0.4712 0.3527

Stimulus Frequency

Table 6 summarises the results of differing stimulus frequencies. Astimulus frequency of 15 Hz yielded the strongest response(Mean=6.319±0.416), while 12 Hz performed slightly poorer while stillyielding a response (Mean 12 Hz=4.754±0.4342). 20 Hz and 30 Hzfrequencies generated no visible response. The presence of harmonicfrequencies was noted for the 12 Hz and 15 Hz stimulus frequencies inthe form of visible peaks at 24 Hz and 30 Hz respectively.

TABLE 6 Response Ratios of Different Frequencies Subject 12 Hz 15 Hz 20Hz 30 Hz 1 5.167 5.912 3.742 2.768 2 4.657 6.015 2.953 2.635 3 4.9776.841 3.164 2.597 4 4.216 6.506 2.817 3.016 Mean 4.754 6.319 3.169 2.754SD 0.416 0.4342 0.4078 0.1894

Epoch Length

Table 7 summarises the results concerning epoch length. A 45 secondepoch had a mean Ratio Response of 7.144±0.513, while a 5 second epochhad a mean Ratio Response of 2.793±0.597, demonstrating the effect ofepoch length on the response.

TABLE 7 Response Ratios of Different Epoch Lengths Subject 5 s 10 s 15 s30 s 45 s 1 3.125 4.263 4.621 7.285 7.617 2 2.838 3.136 3.941 7.3327.519 3 1.939 3.467 4.804 6.373 6.537 4 3.269 2.941 5.546 6.476 6.903Mean 2.793 3.452 4.728 6.865 7.144 SD 0.5967 0.5828 0.6597 0.5137 0.5134

Experiment II

Experiment II evaluated 20 healthy adults (13 males, 7 females,Mage=36.47, SDage=18.54). All 20 participants had 20/20 vision, andsuccessfully completed Experiment II.

The SSVEP parameters used for Experiment II were determined fromExperiment I. Using the portable stimulus system, a flash-reversal imageflickering at 15 Hz recorded for 30 seconds was used. With theseparameters, the mean Ratio Response was 5.551±1.164.

A D'Agostino & Pearson normality test was performed and had a P-value of0.9019, meaning the data were consistent with a Gaussian distribution.

Discussion

In this study we have been able to show that an EEG can reliably detecta 15 Hz SSVEP in normal subjects from a stimulus generated on a portablesmartphone system with the same reliability as a standard LCD monitor.

The proposed system serves as a proof of concept for a dedicatedportable diagnostic system. The results demonstrate that a reliable andconsistent response can be expected from a healthy population. This maybe utilised in the context of sports-related concussion, where anabnormal response may indicate the presence of concussion.

Concussion is currently diagnosed with a clinical diagnosis aided with asymptom checklist, neurocognitive and balance tests. This approach issubjective and prone to observer bias. Conventional imaging modalities,such as computed tomography (CT) and magnetic resonance imaging (MRI)can only be used to rule out severe brain injuries, but cannot detectconcussion.

Conclusion

We have shown that it is possible to reliably detect a steady-statevisual-evoked potential response in healthy controls using a portableplatform. We found that a 15 Hz stimulus, with central fixation targetand a test time of 30 seconds had the most robust, reliable andreproducible results. This testing set-up was achievable with asmartphone, Cardboard headset and a currently-available wireless EEGrecording headset.

Example 3

In a further study, the purpose was to evaluate the utility of aportable SSVEP platform in identifying concussion in rugby union playersand to identify when they are recovered. A prospective cohortobservational study was undertaken over a season of rugby union trainingand match activities. A total of 65 (20.9±2.3 yr.) players were enrolledin the study. Player screening was undertaken to identify any possiblecontraindications to participating in the study, and for history ofconcussion. Tests were performed on a weekly schedule during the rugbyclub's training time.

The visual stimulus utilised for this study (See FIG. 16A) weredisplayed on a Sony Xperia Z1 Compact smartphone in a MP4 video file.The smartphone was placed in a Google Cardboard headset and theparticipant held this to their head covering both eyes. The MP4 videocomprised a sequence of black and white screens alternating at 15 Hz. Anumber was placed in the middle of the screen (occupying less than 2% ofthe screen with a visual angle of 1.5°) to allow participants to focuscentrally to maximise participant concentration and field of viewcovered by the stimulus. This number changed at 5 second intervals toimprove user concentration.

The EEG recordings were undertaken with a wireless, 14-channel EEGheadset (Emotiv EPOC+; Emotiv Systems, Inc. San Francisco, Calif.http://www.emotiv.com). The electrodes were arranged according to theInternational 10-20 system (see FIG. 16B). The O1 and O2 electrodes wereused as the main recording electrodes and the P3 and P4 electrodes wereutilised as a reference point (P3) and for feedback cancellation (P4)respectively. Data was sampled at 128 Hz and wirelessly transferred to alaptop computer (Sony Vaio Pro 11 laptop (Sony Corporation, Minato,Tokyo, Japan)) via the Emotiv Xavier TestBench v3.1.21 software as aEuropean Data Format (EDF) file.

FIG. 16 shows A: An example of the visual stimulus used as the stimulus.The stimulus alternated between the top and bottom picture at a rate of15 times per second. There is a fiducial line in the middle used toalign the screen with the Google Cardboard headset. The number changedat 5 second intervals and participants were instructed to focus on thenumber for a total of 30 seconds. NB: The shadow does not exist on theactual stimulus but is utilised here to make the visual stimulus clearerto view. (B): Emotiv EPOC+ electrode positions. Only electrodes P3, P4,O1 and O2 were utilised: P3 and P4 were utilised as a common-modesubtraction/driven-right-leg reference and ground, and O1 and O2 werethe analysed electrodes.

Prior to the competition season, all enrolled players underwent thescreening assessment. Once enrolled, all participants underwent the EEGtest twice (for test-retest reliability purposes). Throughout thecompetition season, at training sessions typically two days after acompetition game, participants were fitted with the EPOC+ headset andtheir SSVEP acquired. To ensure an adequate connection between theheadset and the participant's head, the Emotiv TestBench software'scontact quality indicator was checked before the test was undertaken. Ifthe quality indicator indicated a poor connection, the headset wasremoved and the electrode pads relubricated with saline solution. Theheadset housing the smartphone was provided to the subject; they wereinstructed to hold it up to their eyes and stare at the number at thecentre of the screen to minimise eye movements for 30 seconds whilsttrying not to blink. The test was then repeated for a total of 2consecutive recordings. Following a head injury, or a medicallydiagnosed concussion, the test was repeated twice to assess for anychanges in the SSVEP. The test was also repeated periodically during theseason for assess for test-retest reliability. To address potentialbias, the administrator of the test did not know the condition of theplayer until after the data was processed.

The captured EDF file data was imported into MATLAB 2015b (MathWorks,Inc., Natick, Mass.; http:www.mathworks.com). A band-pass Butterworthfilter with corner frequencies at 5 Hz and 40 Hz was applied to minimiselower-frequency noise, DC voltage offset and mains power hum. A FastFourier Transformation (FFT) was then applied to generate afrequency-magnitude graph of the combined O1 and O2 channels. Theaverage magnitude (MagAvg) between 5-40 Hz and 15 Hz (Mag15) wascalculated to establish the magnitude ratio (MagRatio) between the Mag15and the MagAvg. The MagRatio was utilised for comparison purposes acrossthe different groups. As each participant had 2 test results, the higherMagRatio results were utilised.

Statistical analysis was performed utilising IBM SPSS software(International Business Machines Corporation, New York, U.S.A.) and thegraphs were plotted in GraphPad Prism 7 (GraphPad Software Inc., CA,U.S.A.). A Shapiro-Wilk normality test determined the data to benormally distributed (control W=0.97; p=0.2902, concussed W=0.96;p=0.4154, recovered W=0.90; p=0.5987). Paired and unpaired single-tailedt-tests were performed between the 3 groups (control-concussed,control-recovered, and concussed-recovered) and a Bonferroni correctionwas utilised for all post-hoc analyses. Test-retest reliability wasestimated utilising the intra-class correlation coefficient (ICC), with95% confidence intervals (CI), to examine agreement between baseline andrepeated testing throughout the season. Cohen's effect size (d) wasutilised to calculate practically meaningful differences betweencontrols, concussed and recovered.

Effect sizes of <0.19, 0.20-0.60, 0.61-1.20 and >1.20 were consideredtrivial, small, moderate, and large, respectively [25]. All summariseddata are expressed as means (with 95% CI) and median (25th to 75thinterquartile range). Statistical significance level was set at α=0.05.

Results

Notable changes were observed in the stimulus response strength(MagRatio) in the identified concussed participants when compared to thecontrol subjects (2.00 [95% CI: 1.83 to 2.16] vs. 5.01 [4.78 to 5.24];p<0.0001) (see Table 1). 8 of the participants who were re-evaluatedafter recovery had an increased MagRatio compared to the concussed SSVEP(see Table 2).

TABLE 8 VEP MagRatio values of total participants and participants thatrecorded a concussion by mean with 95% Confidence Intervals and Medianwith interquartile [25th to 75th] ranges and the differences betweencontrol, concussed and recovered participants. Matched Participants onlyincludes participants who were in all 3 study groups over the season.Mag_(Ratio) score vs. Control vs. Concussed vs. Recovered Group Mean(95% Cl) Median [IQR] diff (p-value); d = diff (p-value); d = diff(p-value); d = Total participants Control 5.01 (4.78-5.24) 4.80[4.07-5.68] — −2.80 (<0.0001); 4.03   +0.02 (0.0117); 0.40 Concussed2.00 (1.83-2.16) 2.00 [1.40-2.32] +2.82 (<0.0001); 4.03  — +2.80(<0.0001); 5.25  Recovered 4.44 (3.90-4.98) 4.82 [4.13-5.18] −0.02(0.0117); 0.40   −2.82 (<0.0001); 5.25  — Matched participants Control4.45 (3.85-5.06) 4.54 [3.79-5.10] — −2.25 (0.0001); 4.20 −0.12 (0.0495);0.17 Concussed 2.20 (2.01-2.38) 2.20 [2.04-2.38] 2.25 (0.0001); 4.20 —−2.47 (0.0002); 3.60 Recovered 4.67 (4.20-5.13) 4.82 [4.13-5.18] 0.12(0.0495); 0.17 −2.47 (0.0002); 3.60 — CI: Confidence Interval; IQR =Interquartile [25^(th) to 75^(th)] range; diff = differences betweenMag_(Ratio); d = Cohen's d effect size

TABLE 9 Player who recorded a concussion response to the visual stimulus(MagRatio) at control (baseline), immediately after concussion, andsubsequent recovery by actual results with differences between thedifferent assessments. Mag_(Ratio) Differences identified Player ControlConcussed Recovered Cont vs. Conc; p-value Conc vs. Rec; p-value Rec vs.Cont; p-value AH 4.52 2.33 4.24 2.19; 0.1970 −1.92; 0.1801 −0.28; 0.0203JH 3.32 2.05 3.10 1.27; 0.1481 −1.05; 0.1280 −0.22; 0.0217 JJ2 4.55 2.314.68 2.24; 0.2008 −2.37; 0.2078   0.13; 0.0088 PC 3.99 2.03 3.77 1.95;0.1996 −1.74; 0.1850 −0.22; 0.0177 TJ 5.09 2.09 5.17 3.00; 0.2522 −3.09;0.2559   0.09; 0.0053 TS 5.35 1.85 5.21 3.50; 0.2882 −3.36; 0.2830−0.14; 0.0083 TG 3.72 2.51 3.48 1.21; 0.1220 −0.98; 0.1027 −0.23; 0.0205LS 5.10 2.40 4.96 2.70; 0.2197 −2.55; 0.2125 −0.15; 0.0092 Total 4.452.20 4.33 2.26; 0.0001 −2.13; 0.0002   0.13; 0.0495 The control ratiowas acquired before a concussion; the concussed ratio up to 72 hoursafter a concussion; the recovered ratio after being clinically declaredto return-to-play; Cont = Control; Conc = Concussed; Rec = Recovered

TABLE 10 Test-retest reliability of the SSVEP and EEG findings forplayers who have undergone multiple testing throughout the season. Med.Group N = ICC (95% CI) Time (IQR) Mean Time Control 22 0.91 (0.79-0.96)36 (26-39) 31.91 ± 11.22 Concussed 3   0.29 (−0.91-0.97) 7 (7-7)  7.00 ±0.00 Recovered 5 0.96 (0.74-0.99) 16 (13-23) 17.60 ± 6.23 

Control test-retest were performed on players periodically over theseason who had not recorded a concussion; Concussed test-retest wereperformed after 3-7 days post-concussion, and not yet clinicallydeclared to return-to-play; Recovered test-retest were performedperiodically on players who were formally concussed but have since beenmedically declared recovered. Med. Time: median time between testing.Mean time: mean time between testing.

A reduction in the alpha rhythms and increase in theta rhythms (8-12 Hz)of concussed participants was also observed. Upon recovery, the alphaand theta rhythms returned to baseline conditions (see FIG. 17).

FIG. 17 shows Fourier transformations of the frequency spectrum (SSVEP)comparisons of player JJ2 when identified with a medically diagnosedconcussed (left) and when medically cleared to return-to-play (right)Note the reduction in alpha rhythm and increase in theta rhythm on theleft figure. Also note the presence of a large peak at 15 Hz on theright figure, demonstrating response to the 15 Hz visual stimulus.

Some control participants also demonstrated a smaller 30 Hz harmonicfrequency in addition to their 15 Hz fundamental frequency (see FIG. 17right). This phenomenon was only observed in 16 control participants,but was not observed in any of the concussed participants.

The study demonstrated the recovery to pre-concussion SSVEP parametersfollowing medically assessed diagnosis of concussion and clinicalrecovery.

The high test-retest reliability for control and recovered groupshighlights the consistency of the measurement, even when the repeatedtesting was conducted several weeks apart.

There are several advantages of using SSVEP compared with conventionalVEP such as: (1) lack of synchronicity between EEG recorder and visualstimulus (simplifying equipment requirements), (2) relative resistanceto noise artefacts; and (3) improved resilience to variable contactimpedance. These advantages make SSVEP a better system for use innon-clinical environments such as on the sideline of sports grounds andin general practitioner surgeries.

The use of imaging modalities such as magnetic resonance imaging (MRI)and computed tomography (CT) are primarily for anatomic imaging, andtherefore provide information about structural problems. As concussionis not a macroscopic structural injury, these imaging modalities do notaid in the diagnosis, but can be utilised to rule out any structuralinjuries. However, VEP testing assesses for function rather thanstructural integrity and reflects the physiology of the brain. Thus, theabsence of the response to the 15 Hz stimulus found in this study mayrepresent an objective assessment criterion for concussion. The use ofVEP's such as the SSVEP utilised in this study has the potential to be asupplemental aid for the assessment of, and identification by a medicalpractitioner in the clinical diagnosis of a concussion.

The background noise was variable even among the same individuals testedagain immediately after their first test. Possible reasons may be dueto: (1) poor impedance control (as the system does not feedback theactual impedance values); and (2) variable visual focus during tests dueto fatigue or distractions. Testing alongside other EEG equipment mayprovide a deeper insight into whether these variances are naturallyoccurring, or a shortcoming of the current equipment. Applying arefractive blur to the stimulus may also identify if pupil, convergenceor accommodation changes affect the responses identified.

The reduction in the alpha rhythm and increase in theta rhythm have beenpreviously reported and this phenomenon may not be exclusivelyattributed to sports-related concussion. Reduced alpha rhythm has beenpreviously associated with drowsiness and sleepiness; increased thetarhythm has been associated with cognitive and emotional processes,particularly stress. Also observed was the presence of a harmonicfrequency in the form of a secondary response at 30 Hz in someparticipants. Previous non-clinical studies have identified thisharmonic frequency, and have leveraged it to improve classificationaccuracy for brain-computer interface solutions. However, its diagnosticutility especially in concussion injuries has yet to be determined. Apossible solution would be to further stratify study groups to identifyif the presence of the harmonic frequency is a random effect or if it isspecific under certain conditions.

In most participants, the second test response was stronger than thefirst. This was hypothesised to be due to familiarisation with theprocess and lessened blinking.

Electroencephalography and SSVEP offers new potential in the assessmentof concussion, by non-invasively and objectively measuring brainfunction. This study undertook to identify if there were differences inconcussed participants utilising SSVEP via a portable device. The studyalso assessed return towards the same individual's previous (baseline)response following a concussive injury.

It is to be understood that, if any prior art publication is referred toherein, such reference does not constitute an admission that thepublication forms a part of the common general knowledge in the art, inAustralia or any other country.

In the claims which follow and in the preceding description of theinvention, except where the context requires otherwise due to expresslanguage or necessary implication, the word “comprise” or variationssuch as “comprises” or “comprising” is used in an inclusive sense, i.e.to specify the presence of the stated features but not to preclude thepresence or addition of further features in various embodiments of theinvention.

1. A head mountable device for detecting a functional disorder of thebrain in a patient, comprising: an LED display; at least one electrodefor measuring electrical potential; the device being configured to bemountable on the head of a patient such that when mounted on the head ofa patient the LED display is positioned before the eyes of a patient andthe at least one electrode is positioned adjacent to the occipital lobeof the patient.
 2. A head mountable display according to claim 1 whereinthe LED display is configured to display a visual stimulus.
 3. A headmountable device according to claim 2 wherein the visual stimulus is alight pulse.
 4. A head mountable device according to claim 2 wherein thevisual stimulus is white light.
 5. A head mountable device according toclaim 3 wherein the visual stimulus pulses at a frequency of between 5Hz to 60 Hz.
 6. A head mountable device according to claim 3 wherein thevisual stimulus pulses at a frequency of 15 Hz.
 7. A head mountabledevice according to any preceding claim wherein the at least oneelectrode is configured to detects electrical signals from the occipitallobe of the patient in response to the visual stimulus when the deviceis mounted on the head of a patient.
 8. A head mountable deviceaccording to any preceding claim comprising a processor configured toreceive electric potential signal data from the at least one electrode.9. A head mountable device further comprising a memory, the memory beingconfigured to store predetermined electrical potential values, whereinthe processor is configured to compare received electric potentialsignal data with predetermined electric potential data to detect afunctional disorder of the brain.
 10. A head mountable device accordingto claim 9 wherein the predetermined electric potential values are atleast one of: amplitude of the electric signal; frequency of theelectric signal; or, latency of the electric signal.
 11. A headmountable device according to any preceding claim wherein the functionaldisorder of the brain is concussion.
 12. A head mountable deviceaccording to any preceding claim further comprising a wirelesstransmitter, the wireless transmitter configured to transmit theelectric potential signal data to the processor over a radiocommunications network.
 13. A head mountable device according to anypreceding claim further comprising a receiver, the receiver configuredto receive activation signals for the LED display, the LED display beingconfigured to display a visual stimulus on receipt of an activationsignal.
 14. A head mountable device according to claim 12 wherein thereceiver is a radio receiver configured to receive activation signalsfrom a computing device across a wireless communications network.
 15. Amethod for detecting a functional disorder of the brain in a patientcomprising the steps of: providing a visual stimulus to a patient;measuring an electrical response of the brain to the visual stimulususing a plurality of electrodes; and, comparing the electrical responseof the brain to predefined electrical data to detect a functionaldisorder of the brain.
 16. A method according to claim 15 implemented ina head mounted device wherein the visual stimulus is provided by an LEDdisplay and the electrical response of the brain is measured by at leastone electrode; the device being configured to be mountable on the headof a patient such that when mounted on the head of a patient the LEDdisplay is positioned before the eyes of a patient and the at least oneelectrode is positioned adjacent to the occipital lobe of the patient.17. A system for detecting a functional disorder of the brain in apatient comprising: a head mountable device according to claim 1; and areceiver for receiving electric potential signal data from the at leastone electrode.
 18. A head mountable device for detecting a functionaldisorder of the brain comprising lighting means for providing a visualstimulus to a patient and at least one electrode to measure an evokedpotential by the brain of the patient to the visual stimulus.
 19. Amethod for detecting a functional disorder of the brain comprising thesteps of providing a visual stimulus to a patient and measuring anevoked potential to the visual stimulus.
 20. A computer program,comprising instructions for controlling a computer to detect afunctional disorder of the brain in a patient as defined in claim
 1. 21.A computer readable medium, providing a computer program in accordancewith claim
 20. 22. A data signal, comprising a computer program inaccordance with claim
 20. 23. A computer program, comprisinginstructions to implement a method in accordance with any one of claim15, 16 or
 19. 24. A computer readable medium, providing a computerprogram in accordance with claim
 23. 25. A data signal, comprising acomputer program in accordance with claim
 23. 26. A system for detectinga functional disorder of the brain in a patient, comprising: a lightsource; at least one electrode for measuring electrical potential; theat least one electrode being configured to be mountable on the head of apatient and positioned adjacent to the occipital lobe of the patient.27. A system according to claim 26 wherein the light source isconfigured to display a visual stimulus.
 28. A system according to claim27 wherein the visual stimulus is a light pulse.
 29. A system accordingto claim 27 wherein the visual stimulus is white light.
 30. A systemaccording to claim 28 wherein the visual stimulus pulses at a frequencyof between 5 Hz to 60 Hz.
 31. A system according to claim 28 wherein thevisual stimulus pulses at a frequency of 15 Hz.
 32. A system accordingto any of claims 26 to 31 wherein the at least one electrode isconfigured to detect electrical signals from the occipital lobe of thepatient in response to the visual stimulus when the at least oneelectrode is mounted on the head of a patient.